Propeller



P 7, 1931- R. SCHALLERT 1,799,192

PROPELLER Filed Aug. 20, 19,28

Eg.7 INVENTOR.

Y W m Guam 4 BY A ORNEYS.

Patented Apr. 7 1931 PATENT OFFIC UNITED STATES 3101mm) SCHALLERT, on NEW You, my.

PROPELLER Application filed August 20,1928; Serial'i'o. 390,676.

The present invention relates to improvements in propellers, for driving airplanes or the like devices.

It is a well known fact that up to-the pres cut time the propellers necessary to give suflicient driving power to air driven machines have been operated at high rates of speed and have required powerful engines to run them at this high speed, when the machines 10. were under load. This has resulted in loss of netlifting and carrying power of such machines due gines.

One of the objects of this invention is to provide a propeller of such shape and design as will adequately reduce the size'of the engine necessary to 'produce the same driving power as the ordinary propellers of common design and usage at thepresent time. 7

A further object is to provide a propeller having increased windage surface and yet requiring less power to run it than the ordinary propeller to produce equal propelling action as such ordinary propeller.- 4

A further object is to provide a propeller 'which'will require slower speed of rotation than the ordinary propeller to develop equal driving power.

With these and other objects in view my 3 invention consists in the novel construction described and-shown in the accompanying specification and drawing.

to the added weight of the en- Referring to the drawings in which similar reference characters denote corresponding parts Fig. ,1 is a view of my propeller looked at along the axis in direction of the arrow of Fig. 2; Fig. 2 is a side elevation'seen 1n the direction of arrow A of Fig. 1; Fig. 3 1s a crosssection of a blade along line 33 of Fig. 2; Fig.4 is a modified construction; 5 is a fragmentary view of a further modlfication showing the essential details thereof; Fig 6 is a perspective view of the device of Figs. 1, 2, 3 and Fig. 7 is a cross sect1on along line 77 of- Fig. 1.

. My device consists of a propeller shaft 10 of any suitable material to which are attached or from which are integrally formed flat wooden or metal blades 11 and 12 of semicircular or other desired form, the planes of said blades being at or approximately at right angles to each otherand each plane also making an angle of approximately with the longitudinal axis of the propeller shaft 10.

The blades 11 and 12 are each provided with partial radial cuts 13 and 14 respective- .ly dividing. their outer curved edgesinto equal sections and thus dividing the two blades into four equal portions 15, 16, 17, 18.

Alternate tips 19, 21, 23,25 of each of-the portions,'wh1ch are the forward tips thereof,

when the propeller is rotatin in direction indicated by the arrow B in ig. 1 and the vehicle is moving forward inthe direction of the arrow of Fig. 2, are bent over-in the manner. indicated in Figs. 3 and 6. The degree of curvature being such as to obtain maximum wind gripping or catching power with minimum windage resistance due to the curvature, and will vary with the size of the propeller. The tips 20, 22, 24, '26 respectively which are the rear blade tips of each blade in this case are uncurved. It will be noted that the curves on the. tipsdo not extend the full length of the blades but only the upper portions C which are approximately half the radial depth of blade are curved. The lower portions D of the, radial depth are straight.

Since the curved tips of my propeller are designed to grip the air and sweep it past the flat portion of the blades it will of course be necessary to reinforce these tips in order that they may stand the added strain. One meth 0d of course would be to furnish suitable guide wires (not shown) attached to the tips and to the propeller shaft.

Another method shown as in Fig. 7 is to add to the strength of the blade in the vicinity of the curved tip by providing a gradual thickening of the blade toward the'edge having the ,curved' portions thus forming a strengthening support for the blade in this region. Stream line design is of course used for this gradual thickening to reduce the v seize a large volume of air about and in front of them and throw it toward the rear along the face proper of the blades and thereby tend to pull the propeller and the vehicle to which it is attached forward with very great force.

Applicant believes that it is the combination of the peculiar shape of his blades, their arrangement relative to each other and the increased surface thereof, that gives him great driving power at slower speed and smaller power input than with the propellers in use at present.

The modification in Fig. 4 is one where very large blades are used. In this case the blades 11 and 12, which are mounted on the propeller shaft 10' in the same manner as are blades 11 and 12 on shaft 10, instead of having one radial cut as before, have a plurality of such similar cuts made dividing each of these blades 11 and 12 into a plurality of individual portions such as 27. Alternate tips 28 of each of said portions 27 are again curved in the same manner as before and each portion gradually thickened as shown in Fig. 7 in the direction of the curved portion. The manner of operation is identical except that greater driving power is obtained.

For lightly loaded vehicles I provide the modification shown in Fig. 5 wherein blades 11 and 12 instead of being semi-circular in shape are plane quadrants of circles the planes of said blades being also approximately at right angles to each other and also making angles of 45 with the shaft 10*. Alternate tips such as 29 are curved in the same manner as before described for Figs.

1 and 4 and the blades are thickened toward the curved portions in the similar manner to that shown in Fig. 7. The operation of this modification is identical to the others.

It is of course obvious that various other modifications of my device are possible without departing from the spirit of my invention and I do not wish to be limited to the modifications shown and described.

lVhat I claim is:

1. An airplane propeller comprising two semi-circular plane blades on a propeller shaft, each blade making substantially an angle of forty-five degrees with said shaft and being substantially at right angles to the other blade and having a radial slit, said blades having bent over portions at alternate ends and at alternate tips formed by said slits, said bent portions constituting air gripping means and means for reinforcing said bent over portions.

2. An airplane propeller comprising semicircular plane blades on a propeller shaft, each blade making substantially an angle of forty-five degrees with said shaft and also being substantially at right angles with the other blade, and having a radial slit, said blades having bent over portions at alternate ends and at alternate tips formed by said slits, said bent over portions constituting air gripping means.

3. An airplane propeller comprising two semi-circular plane blades on a propeller shaft each blade making substantially an angle of forty-five degrees withsaid shaft, and being substantially at right angles to the other blade, bent over alternate tips on said blades and reinforcing means for said bent over tips.

4. A propeller having semi-circular plane blades attached to a propeller shaft at angles to each other, bent over alternate tipson said blades and reinforcing means for said tips.

5. A propeller for air driven vehicles, having semi-circular planeblades attached to a propeller shaft at angles to each other, and having a radial slit, said blades having bent over portions at alternate ends and at alternate tips formed by said slits, said bent over portions constituting air gripping means.

In testimony whereof I afiix my signature.

RICHARD SOHALLERT. 

